Active matter logic for autonomous microfluidics

Francis G Woodhouse,Jörn Dunkel

doi:10.1038/ncomms15169

Francis G Woodhouse, Jörn Dunkel

Open Access

https://doi.org/10.1038/ncomms15169

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Abstract

Chemically or optically powered active matter plays an increasingly important role in materials design, but its computational potential has yet to be explored systematically. The competition between energy consumption and dissipation imposes stringent physical constraints on the information transport in active flow networks, facilitating global optimization strategies that are not well understood. Here, we combine insights from recent microbial experiments with concepts from lattice-field theory and non-equilibrium statistical mechanics to introduce a generic theoretical framework for active matter logic. Highlighting conceptual differences with classical and quantum computation, we demonstrate how the inherent non-locality of incompressible active flow networks can be utilized to construct universal logical operations, Fredkin gates and memory storage in set–reset latches through the synchronized self-organization of many individual network components. Our work lays the conceptual foundation for developing autonomous microfluidic transport devices driven by bacterial fluids, active liquid crystals or chemically engineered motile colloids.

Highlights

Or optically powered active matter plays an increasingly important role in materials design, but its computational potential has yet to be explored systematically
The balance of energy uptake and dissipation forces a microbial or ATP-driven fluid to travel at a preferred speed along microchannels[19], while fluid incompressibility imposes topological constraints on the flow network dynamics that enable the implementation of logical operations
Our mathematical approach towards describing active flow networks (AFNs) takes direct guidance from recent experiments[19] demonstrating that highly concentrated suspensions of Bacillus subtilis bacteria spontaneously selforganize into stable unidirectional flows when confined in narrow microfluidic channels

Summary

Introduction

Or optically powered active matter plays an increasingly important role in materials design, but its computational potential has yet to be explored systematically. An important subgroup of active materials is fluid-based[2], encompassing ATP-driven liquid crystals[9,10], bromine-fueled squirmer droplets[11], Janus particles[12,13,14], colloidal rollers[15] and microbial suspensions[16,17] These systems are central to current microfluidic soft robotics research[18] owing to their ability to self-assemble into complex structures[12,13,14], spontaneously create unidirectional flows[19] and transport microcargos[7,20]. A compact mathematical description of AFNs is made possible by a recently proposed mapping onto an effective lattice-field theory[29] We use this generic framework to construct active matter logic (AML): we implement universal logical operations, reversible gates and memory storage in set–reset (SR) latches through the synchronized action of many individual AFN components. We evaluate the robustness of AFN-based computation against noise

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